Mild,Efficient, and Rapid Dehydration of Aldoximes to Nitriles Mediated by Phthalic Anhydride Under Microwave Irradiation

Summary.  Aldoximes can be efficiently and rapidly dehydrated to nitriles by treatment with phthalic anhydride under microwave irradiation. Received April 18, 2001. Accepted (revised) June 7, 2001     

PAMS基凝胶型聚合物锂电池的制备及电化学性能表征

An admixture of acrylonitrile, methyl methacrylate, styrene and commercial liquid electrolyte (LB302, 1 mol/L solution of LiPF6 in 1∶1 EC/DEC) was enclosed in CR2032 cells. The assembled cells were then γ-ray irradiated using configurations of LiNi0.8Co0.2O2/Li half cells. Through this in-situ irradiation polymerization process, rechargeable lithium cells with poly(acrylonitrile-co-methyl methacrylate-co-styrene) (PAMS) were obtained based gel polymer electrolytes. The structure and thermal stability of PAMS were characterized by FT IR and DSC analyses. The electrochemical properties and charge discharge performance of PAMS-based gel-polymer lithium cells were evaluated by AC impedance spectroscopy, cyclic voltammetry and gavanostatic battery cycling. The results indicate that the in-situ gama-ray irradiation approach is convenient to prepare gel-polymer lithium cells with good charge-discharge performance.     

Modeling of SIMS profiles at low energy: Application to algaas

Abstract

This work proposes an original solution to model Secondary Ions Mass Spectrometry. This modeling allows the accurate determination of both the thickness and the composition of AlGaAs samples.     

Neutron diffraction study of anisotropy of crystal lattice compression in irradiated of fast neutron high-T c superconductors YBa2Cu3O6·95 and La1·83Sr0·17CuO4 under pressure

Abstract

The structural changes in the high temperature superconductors (HTSC) samples of the compounds YBa₂Cu₃O_6·95 and La_1·83Sr_0·17CuO₄ under pressure being unirradiated and irradiated by fast neutrons have been studied by the neutron diffraction method. The different anisotropy of crystal lattice compression was found for these compounds in the initial and irradiated states.     

Introducing a new optimization tool for femtosecond laser-induced surface texturing on titanium,stainless steel,aluminum and copper

The surface micro- and nano-scale features produced by femtosecond laser irradiation on titanium, stainless steel, aluminum and copper are reported in this work. Each observed surface microstructure, which was fabricated from a particular combination of four adjustable parameters, can be characterized by the fluence and pulses-per-spot (F-PPS) and accumulated fluence profile (AFP) models. By performing a wide screening of the experimental space, we have successfully mapped the evolution of microstructures as a function of two variables per model. We have also shown that these two models, in conjunction with one another and the data that we have presented, can be used as an optimization tool for scientists and engineers to quickly fine-tune the laser processing settings necessary for a desired surface topography. In addition, the electron–phonon coupling strength and thermal conductivity have been identified as the material properties that have the largest influence over the achievable surface patterns on metallic substrates.     

Degradation in polytetrafluoro ethylene by 62 mev protons

The aim of our study is to describe the dose dependent proton induced modifications in Polytetrafluoro ethylene (PTFE) by using Fourier Transform Infra-red spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC) and X-ray diffraction analysis (XRD). The shifting of the main peak along with a decrease in its intensity, the decrease in thermal stability and melting point and the formation of stable free radicals were observed in the polymer by proton irradiation.     

Ultrasound assisted co-precipitation of nanostructured CuO–ZnO–Al2O3 over HZSM-5: Effect of precursor and irradiation power on nanocatalyst properties and catalytic performance for direct syngas to DME

Nanostructured CuO–ZnO–Al₂O₃/HZSM-5 was synthesized from nitrate and acetate precursors using ultrasound assisted co-precipitation method under different irradiation powers. The CuO–ZnO–Al₂O₃/HZSM-5 nanocatalysts were characterized using XRD, FESEM, BET, FTIR and EDX Dot-mapping analyses. The results indicated precursor type and irradiation power have significant influences on phase structure, morphology, surface area and functional groups. It was observed that the acetate formulated CuO–ZnO–Al₂O₃/HZSM-5 nanocatalyst have smaller CuO crystals with better dispersion and stronger interaction between components in comparison to nitrate based nanocatalysts. Ultrasound assisted co-precipitation synthesis method resulted in nanocatalyst with more uniform morphology compared to conventional method and increasing irradiation power yields smaller particles with better dispersion and higher surface area. Additionally the crystallinity of CuO is lower at high irradiation powers leading to stronger interaction between metal oxides. The nanocatalysts performance were tested at 200–300 °C, 10–40 bar and space velocity of 18,000–36,000 cm³/g h with the inlet gas composition of H₂/CO = 2/1 in a stainless steel autoclave reactor. The acetate based nanocatalysts irradiated with higher levels of power exhibited better reactivity in terms of CO conversion and DME yield. While there is an optimal temperature for CO conversion and DME yield in direct synthesis of DME, CO conversion and DME yield both increase with the pressure increase. Furthermore ultrasound assisted co-precipitation method yields more stable CuO–ZnO–Al₂O₃/HZSM-5 nanocatalyst while conventional precipitated nanocatalyst lost their activity ca. 18% and 58% in terms of CO conversion and DME yield respectively in 24 h time on stream test.     

New Synthesis of [1,3,4] Thiadiazolo [2,3-C][1,2,4] Triazinone; Transfer of Active Electron by Microwaves

Reaction of various aromatic aldehydes with 4-amino-6-methyl-1,2,4-triazin-5-one supported on to montmorillonite-K10 in the presence of nitrobenzene under microwaves irradiation, afforded the corresponding [1,3,4] thiadiazole [2,3-c][1,2,4]-triazinones.     

New Bisabolane Sesquiterpenes from the Rhizomes of Curcuma xanthorrhiza Roxb. and Their Inhibitory Effects on UVB‐Induced MMP‐1 Expression in Human Keratinocytes

Two new bisabolane sesquiterpenoids, 1 and 2 , along with five known ones, 13‐hydroxyxanthorrhizol ( 3 ), 12,13‐epoxyxanthorrhizol ( 4 ), xanthorrhizol ( 5 ), β‐curcumene ( 6 ), and β‐bisabolol ( 7 ), were isolated from the rhizomes of Curcuma xanthorrhiza Roxb . The chemical structures of the new compounds were determined to be (7R,10R)‐10,11‐dihydro‐10,11‐dihydroxyxanthorrhizol 3‐O‐β‐D ‐glucopyranoside ( 1 ) and (?)‐curcuhydroquinone 2,5‐di‐O‐β‐D ‐glucopyranoside ( 2 ) on the basis of 1D‐ and 2D‐NMR spectroscopic analyses and optical‐rotation characteristics. Compounds 2 and 3 decreased MMP‐1 expression in UVB‐treated human keratinocytes by ca. 8.9‐ and 7.6‐fold at the mRNA level, and by ca. 9.2‐ and 6.6‐fold at the protein level, respectively. The results indicate that the isolated compounds may have anti‐aging effects through inhibition of MMP‐1 expression in skin cells.     

Reaction control by a host-guest complexation method

Very successful stereo-, regio-, and enantio-controls of the photoreaction of a guest compound were achieved by irradiation of the host-guest complex in the solid state. In order to discover the reason for the successful control, the X-ray crystal structure of the complex was studied. The complexation method was also effective to freeze the equilibrium in solution and isolate the labile tautomeric isomer as an inclusion complex.